Electronic systems, such as computer systems, rely for proper operation on the transmission of electric signals among the various components of the system. In a computer system, for example, electric signals must be transmitted between the computer and a keyboard, a video monitor, a mouse, and any other peripheral electronic devices coupled to the computer. The phrase “peripheral device” will be used herein to mean any electronic device coupled to a computer or forming a part of any electronic system, including a keyboard, a video monitor, and a mouse.
Under certain circumstances it may be desirable to place the computer in one location and to place the peripheral devices in another location separated from the computer's location by a certain distance. Category 5 (CAT5) cable or similar cable is often used for the purpose of carrying electric signals between the computer and the peripheral devices. It is well known that an electric signal becomes attenuated as it travels along a cable, and that the degree of attenuation is directly proportional to the length of the cable. Such attenuation can be compensated for by appropriately boosting or otherwise filtering the electric signal in order to return it to its original characteristics. The amount of compensation required in order to properly filter an electric signal will be referred to herein as a “compensation factor.” The term “filter signal” will be used herein to refer to the supplemental electric signal that, when added to the electric signal, compensates for any attenuation and restores the electric signal to its original characteristics. The filter signal for a particular electric signal is generated by a device or a circuit that has been configured by taking into account the compensation factor.
A reason for wanting to compensate for attenuated electrical signals becomes apparent when an analog, high-resolution video signal, for example, is transmitted along a long series of conductors. As cable length increases, the video signal becomes increasingly distorted and blurry, leading to user fatigue and loss of usefulness of the video signal.
One of ordinary skill in the art will recognize that a well known method for measuring the length of a conductor is to use various forms of a Time Domain Reflectometer, or TDR. A TDR is capable of taking extremely high accuracy measurements, but the expense and manual intervention required are prohibitive where an inexpensive and automatic method can be used. An automatic compensation system is desirable because it requires less user intervention than a manual compensation system. However, while they function well, the existing automatic compensation systems are expensive and complicated. Accordingly, there exists a need for a simple and inexpensive system and method capable of automatically determining a compensation factor and/or a filter signal needed to compensate for an attenuated electric signal in an electronic system.
For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present invention. The same reference numerals in different figures denote the same elements.
The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “comprise,” “include,” “have,” and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. The term “coupled,” as used herein, is defined as directly or indirectly connected in an electrical, mechanical, or other manner.